This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: MCB102 Quiz #1 9/13 Please write your name on the back of the quiz. You may use pencil or pen. Question 1 (6 points) The following is a peptide at pH 7: H H O H O H O H O H O H O H N+ C C N C C N C C N C C N C C N C C OH HCCH3 H CH2 CH2 H CH2 H CH2 H H H2C CH2 CH2 CH2 SH CH3 S CH3 1a. For the first 2 amino acids of this peptide, fill out the following table. Full name 3-letter abbreviation 1-letter abbreviation R group classification AA#1: AA#2: 1b. Draw a triangle around the alpha carbon(s) that is (are) NOT chiral. Circle the R group(s) of the amino acid(s) often found in tight beta turns. Put a box around the R group(s) of the amino acid(s) that can form disulfide bonds. Draw arrows pointing to the bonds of the third amino acid whose angles are plotted in the Ramachandran plot. MCB102 Quiz #1 9/13 Question 2 (5 points) Describe the structure of a beta sheet. What does the backbone look like and where are the R groups? What noncovalent interactions are primarily responsible for the structure? Be specific about the functional groups involved in these interactions. You may draw a picture if you wish. (Maximum length: 4 sentences) Question 3 (5 points) log 4 = 0.60 log 3 = 0.47 log 2= 0.30 log 1 = 0 log (1/2) = -0.30 log (1/3) = -0.47 log (1/4) = -0.60 + H+ Acetic acid Acetate A solution contains 0.2 M acetic acid (pKa = 4.8) and 0.1 M acetate. What is the pH of this buffer? MCB102 Quiz #1 9/13 Question 4 (4 points) Based on the information given in question 3, which graph (A, B, C or D) represents the most likely titration curve for acetic acid? Explain your answer. (Maximum length: 3 sentences) ...
View Full Document
- Spring '08